//x的平方根
//测试链接 https://leetcode.cn/problems/sqrtx/
public class MySqrt {
    public int mySqrt(int x) {
        if(x < 1){
            return 0;
        }
        long left = 1, right = x;
        while(left < right){
            long mid = left + (right - left + 1)/2;
            if(mid*mid <= x){
                left =  mid;
            }else{
                right = mid - 1;
            }
        }
        return (int)left;
    }
}
